Ignore if physical interface mac is not set in agent.conf (DPDK case).
Ignore if physical interface mac is not set in agent.conf (DPDK case).

Change-Id: I57e52c20bca10cac91a6c1c40a3c405ba3be7199
closes-bug: #1663775

eonpatapon/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller